Several generally known gasification processes use a similar method for setting of casting or molding sand. There includes firstly the SO.sub.2 method, in which basically poisonous liquid SO.sub.2 is used. In the Betaset method, methyl formate is used as a gas; whereas amine gas is used in the Coldbox method. All of these methods use the same principle described above and utilize costly gases that require disposal after the setting operation.
A method of this kind is described in DE 31 35 510 Al. In this disclosure, the setting liquid measured for a casting mold is first mixed with air. The mixture is completely gasified with the addition of energy and then supplied to a gassing plate of the molding box, from which a quantity of setting gas penetrates the molding sand to be set. Although this method has the advantage that only the amount of liquid intended for a casting mold is gasified, the amount added must be made quite generous for safety reasons, so that the molding sand sets completely. It is also necessary to be sure that a portion of the gas can escape through pipe seals on the transport path from the metering and gassing device to the molding box, but there is the particular danger that a portion of the gas will condense again along this path and hence be lost to the molding sand loaded into the box for setting it. To prevent this condensate from forming, it is conventional to heat the pipes leading to the casting mold, but this is very difficult as well as expensive.